Poor Customer Service

I am not happy with their customer service. I took my car for Diagnostics at the Eastern Cape Motors because the service light on my car keeps on popping up with a (Service engine now) on the dashboard screen. I took it Eastern Cape Motors, I waited 6 hours for them to come back to me. When I got back there to fetch my car, they said that they had not found any problem with the car and they have just resetted the service light, thereafter I paid and I left with the car. A few km away from their Ford Service warehouse, the light came up again. I drove it back to Eastern Cape Motors and they asked if I could leave the car there and fetch it the following day. The following day came and the problem was still not found as to what causes the light to pop up and the message, mind you I was not being updated as to what was happening and I had call myself to always check on them on what was going on with my car. My car has been there for 2 days and I still did not received any update so I took the liberty of calling and checking up. I was then informed that they cannot find the problem and that they have worked on my car for 2 days and if I wanted them to work on my car for any longer I would have to pay them R4000. How is that a dedicated and trusted Ford service department cannot find what is wrong with a Ford Car and furthermore tell me that if I want any further assistance on find what is wrong with my car I must then cough up R4000 for them to help me. This is absurd and very Poor Customer service.